1. Field of the Invention
The present invention relates to an elasticity measuring method of measuring a value representative of a level of elasticity of an elastic body, for example, an elastic rubber, an organism or a living body, etc., which is soft and rather incompressible, by means of measuring an internal strain using energy such as ultrasounds, an X-ray, and magnetism, where said value may be referred to as "elastic value" or "elastic constant" hereinafter, and includes, for example, typically shear modulus, Young's modulus, etc.; and an elasticity measuring apparatus, which is adapted to practice such an elasticity measuring method, and to be incorporated into, for example, a non-destructive inspection equipment, an image diagnostic system in which the elastic constant of the human body is measured, and upon being regarded as an organized body, an organized body diagnosis is implemented, and the like.
2. Description of the Related Art
Hitherto, the elastic constant of a uniform quality of elastic rubber or the like is determined in such a manner that a test material shaped as a board is set up to a tension tester to measure both stress and strain , so that the elastic constant is calculated. With regard to a living body, for example, in case of a checkup for breast cancer, a doctor examines stiffness of the object through the palpation.
With respect to industrial products such as the elastic rubber, it is theoretically possible, after they are processed in a format of the product such as a tire or the like, to conduct the diagnosis as to whether the inside of the product is provided with a uniform elasticity. This will be implemented in such a way that the force is applied from the outside to the industrial product to induce the strain , and at that time the stress distribution of the product and the strain distribution of the inside thereof are all measured so that the distribution of the elastic constant can be detected and visibly displayed on a display unit. However, indeed, it is very difficult to measure the stress distribution of the surface of the products as well as the stress distribution of the inside of the products. Thus, it is actually almost impossible to implement the diagnosis as to whether the inside of the product is provided with a uniform elasticity.
Further, the palpation practiced for a living body involves problems, because it depends on a doctor's sense or feeling and thus lacks a determinability. Furthermore, it is difficult to diagnose a lesion organization, such as the liver cancer, which hides far back in the internal organs. Still further, even if it is desired that the distribution of the elastic constant is detected in accordance with the stress distribution of a surface of the living body and the strain distribution of the inside thereof, it is more difficult, in comparison with that in case of the industrial products, to measure the stress distribution of a surface of the living body. For example, now, even if it is desired that the elastic constant of the liver tissue is detected in accordance with the strain of the liver due to the pulsation of the heart, it is impossible to measure the stress distribution of the liver. It may be considered that a low frequency of motion is generated by means of applying from the outside the vibration with a predetermined force and a predetermined velocity using a vibrator-like something, or a static deformation is provided by means of pushing using a spread board-like configuration of something. However, it is almost impossible to measure the stress distribution of the inside and it is even difficult to measure the stress distribution of a skin surface of the living body.